Container, and method and machinery for producing same



Feb. 25, 1964 B; EDWARDS 3,121,916

CONTAINER, AND METHOD AND MACHINERY FOR PRoDUcING lSAME 'original Filedsept. 17, 1959 s sheets-sheet 1 INVENToR. Bryan? Edwards BY LA Qu? Feb.25, 1964 B. EDWARDS 3,121,916

CONTAINER, AND METHOD AND MACHINERY FDR PRoDucING SAME Original FiledSept. 17, 1959 8 Sheets-Sheet 2 Figi IN VEN TOR.

ryanzz Edwards Bv 8 Sheets-Sheet 3 l" I NN: l

INVENTOR.

www@ a@ 4Feb. 25, 1964 B. EDWARDS CONTAINER, AND METHOD AND MACHINERYRoR PRoDUcING SAME Original Filed Sept. -1'7, 1959 Feb. 25, 1964 B.EDWARDS CONTAINER, AND METHOD AND MACHINERY FOR PRODUCING SAME 8Sheets-Sheet 4 Original Filed Sept. 1'?, 1959 USNRQEL ZIB M @A a@ Feb.25 19.64 B. EDWARDS 3,121,915

CONTAINER, AND METHOD AND MACHINERY 'FDR PRoDucING SAME original Filedsept. 17, 1959 8 sheets-sheet A5 |73 es /A l 1:19.61 \|82 A 111W/'ENTOR-I Brycmi Edwards BY @LA M ME Feb. 25 1964 B. EDWARDSCONTAINER, AND METHOD AND MACHINERY FOR PRODUCING SAME 8 Sheets-Sheet 6Original Filed Sept. 17, 1959 INVENToR. Bryan? Edwards BY Feb. 25, 1964B. EDWARDS 3,121,915

CONTAINER, AND METHOD AND MACHINERY EDR PEoDUcING sAME original Filedsept. 17, 1959 8 sheets-sheet v IN VEN TOR.

Bryan Edwards BY Feb. 25, 1964 Original Filed'Sept. 17, 1959 B. EDWARDSCONTAINER, AND METHOD AND MACHINERY FOR PRODUCING SAME a sheets-Sheet 8if 2.9:: 8G ZIA' |66' v l fig) /ZIB' l V70" L25 nl kv-W PnNMv^|Tlf`vVvwN.ww/NIHM vx l 226 n n 'New m F19. 16 I I I r/faa INVENTOR. Bryan?Edwards BY www.

United States Patent O 3,l2l,916 CN'EAINER, AND METHD AND MACHINERY FRPRDUCENG SAME Bryant Edwards, @ah Park, lil., assigner to Illinois ToolWorks Ine., Chicago, iii., a corporation of Deiaware @riginalapplication Sept. i7, 1959, Ser. No. 840,604, now Patent No. 3,959,319,dated Get. 23, 1962. Divided and this appiieation Feb. 23, 1962, Ser.No. 175,258

Ciairns. (Ci. IS-i9) This invention relates in general to containersformed of plastic material and, more particularly, relates to thin wallplastic containers which are formed with a false bottom, that is to say,a bottom which is concaved axially upwardly a predetermined distanceabove the outer and visible side Walls of a container.

rIlhere has existed a long-felt need for a thin walled plastic containerhaving a false bottom. An advantage that accrues to a false bottomcontainer, over a container having the bottom wall at the base of theside walls, relates to the stacking of a plurality of empty containersin telescoped relation in a manner to quickly facilitate easy removalthereof. The false bottoms, it will be apparent on reflection, space theindividual containers one from the other in a manner not requiringauxiliary lugs or stacking rings which are often necessary on nonfalsebottom containers. The stacking feature is very important in containersto be associated with automatic equipment.

When thin wall plastic liush bottom containers are utilized with hotbeverages, the heat from the beverage may damage surfaces upon which aflush bottom container is deposited. With a false bottom container, thissituation is alleviated. In certain automatic vending machinesdispensing hot beverages into containers, a false bottom container isfound to be very useful in manual transportation of a filled containerfrom the vending machine to the piace of consumption. The constructionof the false bottom container to be described in detail hereinafter isparticularly advantageous in this regard due to the double thickness ofthe skirt portion defining the so-called false bottom.

A particularly important area of application of thin wall plasticcontainers of the false bottom variety is in the so-called throw-away ordisposable container eld. The particular problems involved relate toetiicient manufacture of a container so as to be competitive withconventional containers while retaining the advantages that accrue toplastic materials. The articles to be later described in detail, thatform a part of this invention, have the requisite strength, are easilyformed in large numbers by mass manufacturing techniques, areaesthetically pleasing, and are otherwise well adapted for theirintended purposes.

It has been found that one eflcient manner of producing containers andthe like involves their being molded from sheet thermoplastic material.This method contemplates warming the material, mechanically drawing itto a partially completed form, blowing air under pressure thereinto toform the material into the configuration of a cavity or mold and thenimmediately, while the formed plastic material is still in a heatedpliable and plastic form, causing relative movement of certain parts ofthe plastic material in turn to cause a portion of the previously`formed plastic material to adhere back upon itself to provide a novelfalse bottom container of superior characteristics. This inventionrelates to the novel container, improvements in a machine for producingsuperior false bottom container, and the novel methods of producing saidcontainer.

In my co-pendin-g application entitled Container Molding Machine havingSerial No. 763,668, filed on September ice 26, 1958, and now abandoned,I disclosed a machine wherein the plastic sheet is pre-stretchedbiaxially to accomplish molecular orientation in the sheet material,clamping or support means for holding a given area of the plasticmaterial before and during the mechanical drawing of the material, andbefore any portion of the sheet material engages a complementary mold ordie, improved mandrels or male die members which have controlledfrictional and heat transfer characteristics, improved means for sealingoff and shearing selected area of plastic sheet material all of whichformed containers of improved uniform characteristics and of a superiorfinish.

I have elected to show a modification of the aboveidentified machinewhich will readily produce my novel false bottom containers. While Ihave elected to show a machine of the general characteristics of theaforementioned copending application, it will become obvious throughoutthe specification that there are other and different machines adaptableto producing my novel containers which may be used with equal facilityas the instantly disclosed machine.

It is an object of this invention to p-rovide a thin wall container witha novel false bottom feature having the characteristic of an annulardepending side wall skirt portion, the cross-Sectional thickness of thesaid depending skirt portion being substantial-ly double the wallthickness of the remainder of the container.

It is still another object of this invention to disclose a method oftaking a preformed container, and while it is still in a plastic stageand by means hereinafter disclosed, causing portions of the preformedcontainer to be moved and thereafter to adhere to the adjoiningcontainer side wall thereby to provide the novel false bottom plasticcontainer.

It is further, an object of this invention to provide an improvedmachine for practicing the methods by which the novel container may beformed.

The novel features that are characteristic to the invention are setforth with particularity in the appended claims. The invention itself,however, both as to its organization and its method of operation,together with additional objects and advantages thereof, will 'best beunderstood by the following description of the specific embodiments whenread in connection with the accompartying drawings in which:

FIG. 1 is a side view of a machine constructed in accordance with theprinciples of this invention for making thin wall plastic containershaving a false bottom;

FIG. 2 is a vertical cross-sectional view through the machine as takenalong line 2-2 in FIG. 1;

FIG. 3 is a horizontal cross-sectional view through the machine as takenalong line 3--3 of FIG. l;

FIG. 4 is a view somewhat similar to FIG. 3 and showing a modificationof the machine where the plastic sheet stock, or web is stretchedbiaxiallyg FIG. 5 is an enlarged fragmentary vertical sectional viewthrough the mold cavity showing the male member or mandrel beforeinitial drawing of the sheet material astaken along line 5-5- of FIG. 2;

FIG. 6 is a view similar to FIG. 5 showing the relative relationship ofthe parts following the mechanical drawing of the web;

FIG. 7 is a fragmentary View similar to FIG. 6 showing a subsequent stepin the operation;

FIGS. 8 through 10 are views similar to FIG. 7 showing the nextsucceeding steps in the operation of the device;

FIG. ll is an enlarged fragmentary sectional view of the lowerright-hand corner of FIG. 8 of the drawings;

FIG. 12 is an enlarged fragmentary sectional View of the lowerright-hand corner of FIG. 10 of the drawings;

FIG. 13 is a fragmentary sectional view showing the relationship of aplurality of false bottom containers when they are placed in stackedrelation;

FIG. 14 is a semidiagramrnatic isometric perspective view, with portionsbeing broken away, illustrating the relative movement of the variousparts of the machine to produce the false bottom container;

FIG. 14a is a semidiagrammatic view of an alternate method ofaccomplishing movement of the knockout plug relative to the female moldmember during and after the formation of the false bottom container.

FIGS. 15 through 17 are views similar to FIGS. 7 through 9 showing analternative method of making a false bottom container.

ln the art of forming containers and the like from plastic materials ofthe thermoplastic variety, two major methods have been used heretofore,namely, that of injection molding and the second type which may bedesignated as pressure molding. In the latter method a pressuredifferential is created across a web or membrane of thermoplasticmaterial to cause it to move into engagement with a mold member. Methodsto be discussed hereinafter in greater detail generally relate to thesecond type of molding process, but the preferred method employs acombination of use of pressure differentials along with a mechanicaldrawing of the sheet material to achieve the desired results.

While containers may be formed by a blow molding or vacuum moldingprocess without any mechanical engagement of the web of heatedthermoplastic material to form the container, I have found that moreuniform results are obtained by mechanically drawing the heatedthermoplastic material with a mandrel to cause the major deformation ofthe web or sheet stock, then clampingly engaging the drawn materialaround the periphery of a chilled mold member, and then introducing afluid pressure differential (preferably air pressure differential) tothe drawn web or film of material to cause it to separate from themandrel and quickly engage the cooled mold cavity. I have found that ifthe bottom or end surface of the mold cavity is not chilled as is therest of the cavity (and in some cases even is heated), then thecomplementary portion of the container which initially engages thebottom surface of the mold cavity may be displaced from this preformedstage and literally may be lifted or moved towards the open end of thecontainer to a position it had assumed when the pressure differentialwas first created. When moving the bottom portion to its second positionas just discussed, i! is important to avoid stretching the material atthe juncture of the side walls and bottom of the container as this wouldweaken the area substantially. I have found that by using the apparatusand methods which I am hereby disclosing the bottom-most portion of theside walls of the container adjacent the bottom of the container in thepreformed stage n ay be folded back upon themselves, which foldint7affords several important results.

One of these results is to assure that there is no interA ruption in thecontainer wall. This is exceedingly important for containers of the typewhich hold fluid beveragesand the like. A second result of this foldingback of the bottom-most portion of the side walls upon themselves isthat a double-wall, strong, rigid skirt is provided which will supportthe container when filled. The skirt is a single continuation of thesurface of the container which is never broken. The edge or bottom-mostportion of the skirt represents the crease of the fold. It will berecognize that the foregoing is important since this double wall skirtmust support the entire receptacle when filled and thus since manycontainers of plastic are thin walled (being measured in thousandths ofan inch, i.e., .005 to .020), reinforcing by the supporting skirtportion is truly significant.

Another important feature contemplated by this method is that, as thedouble walls of the skirts are formed by being folded back uponthemselves as previ- CFI ously described, the adjoining surfaces of thedouble walls are caused to adhere to each other. Assurance is therebyprodived that the skirt portions will not be spaced apart and actingindependently or separately. The adhering of the folded side walls toeach other also allows the bottom wall to be integrally joined with theupper side walls of the cup for support thereby, as well as beingsupported from below by the depending double thickness skirt.

A further feature of the double thickened skirt at the bottom end of thecontainer is that it serves, together with the normally folded overrolled lip at the open end of the container, as a convenient place for aperson to support a very hot beverage since the thermo-conductioncharacteristic of the doubly thickened portion (Le. the rim and thedepending skirt) is less than that of the relatively thinner sideportions and affords a person cooler places to carry and support suchhot beverages. Another aspect of the sealed skirt portion is that itprevents the lodging of small food particles in the crevises andcrannies that would appear in this area if it were not sealed. This isparticularly important in re-usable containers that reA quire cleaning.

Time, in my process, is a very important factor in accomplishing themoving of the bottom wall and a por4 tion of the side walls from theirpreformed positions to their final positions. The time interval betweenthe imposition of the pressure differential to the hot thermoplasticmaterial to accomplish the initial performing, and the step of movingthe bottom wall and a portion of the side walls to their final positionmust be exceedingly short.

To insure a good tight seal of the bottom wall portion of the containerwith the upper side walls of the container, after it has been raisedfrom the preformed position, I have found that it is expeditious to forman annular inwardly directed shoulder in the mold which assures contactof the marginal edge of the bottom portion with the upper side wallportions to allow the material to reunite or flow together. Since themold cavity surrounding this internal shoulder is cool, it is apparentthat the movement of the bottom portion must be quickly accomplished inorder to join the materials prior to setting thereof.

As will become apparent by the specific discussion of the methods andmachine by which I provide this novel false bottom container, I haveinvented two major methods by which the bottom portion and bottom sidewall parts of the preformed container may be moved from their preformedposition to their final position. The first method is to do itmechanically with a heated (or at least relatively warm) movable endportion of the mold cavity, the movement of the end portion of thecavity being accomplished by a cam actuation off a drive shaft which hasthe advantage of being adjustable to accommodate a large number ofdifferent mold sizes and rapid stroke changes. An alternative to camactuation is pneumatic actuation using the same air supply as disclosedherein for the initial preforming stage and by merely placing anotheroutlet to the air supply at the pneumatic actuator downstream of theoutlet which creates the pressure differential. The time differentialnecessary between preforming and moving the bottom portion of the moldcavity upwardly is afforded by the short time interval it takes thepressure front to traverse the distance between the upstream outlet anddownstream outlet at the pneumatic actuator.

The second major method of forming the false bottom container isbasically that of using the male mold member or mandrel which does theinitial mechanical drawing as an abutment means in the third operationsubsequent to the second operation which may be called the preformingstage. In the third operation, the mandrel is re-engaged with the web ofmaterial and serves as an abutment means stopping the bottom portions ofthe ccntainer in its finally formed position. The movement of the endportion of the preformed container from the sccond or preforming stageto the third and final stage being accomplished by reversing thepressure differential of the preformed stage so as to cause the bottomportions of the container to move in the reversed direction from themovement in the preforming stage for abutment against an internalshoulder of the mold and the end surface of the male mandrel.

While the foregoing has been discussed in quite general terms, it isbelieved that it will serve as an introduction to the understanding ofthe more detailed discussion that will now follow.

Referring now in greater particularity to the drawings, and iirst toFIGS. l to 3, there is shown a machine Sil for molding containers, suchas false bottom cups, from plastic sheet material. While thisspecification will discuss this invention in terms of cups, the termshould not be considered limiting as the invention has application toarticles of many natures and uses. The machine includes a frame 32.having thereon a drive motor 3d driving a speed reducer 36. The speedreducer drives a chain 37 which in turn drives a shaft 38. The shaft 3Sis provided at its opposite ends with cams 40 cooperable with camfollowers or rollens d2 at the lower ends of push rods d'4 journaled ina cross member 4d of the frame l32 and further guided by guides orsleeves i3 adjacent the lower ends of the push rod ed. The push rods 44support at their upper ends a horizontal cross head 5t). The push rodsare provided with rollers 52 coaxial with the rollers 42. and theserollers 52 are positively forced down by the cam flanges 54 axiallydirected on arms 56 secured at the ends of the shaft 38 outwardly of thecams dil.

The shaft Y35S is journaled in bearings 58 supported from a transverseportion vSti of the frame, the bearings being spaced in from the ends ofthe shaft. Between these bearings and adjacent thereto the shaft isprovided with a pair of cams 6,2 cooperable with cam followers 64 at thelower ends of push rods 66 journaled in bushings or the like e8 mountedon a fixed central plate portion e9 of the frame. A mold 70, having aplurality of cavities therein, and subsequently to be discussed ingreater detail, is supported at the tops of the push rods 6e forvertical movement as controlled by the cams 62. The mold or die 'il isprovided with lateral base extension '72 cooperable with a iixed member74 on the frame portion e9 to the guide the mold means or die 7i); invertical movement.

The transverse frame member 46 is provided with a depressed centralsection 76 having a pair of bushings 7S mounted thereon. Posts orconnecting rods Se extend vertically through these bushings and throughaligned apertures in the depressed central section 7d of transverseframe member d6. The connecting rods or posts Sil are fixed at theirupper ends to cross head Sti and move vertically therewith. Theconnection is a screw set arrangement, as will be seen particularly inFlG. Z and this allows for a certain amount of vertical adjustment.Molding head S2 is secured to the bottom of the posts or connecting rodsSi? and includes a plurality of downwardly directed mandrels or male diemembers e4 aligned with corresponding cavities 36 in the mold 70. In thespecific illustrative embodiment, there are two rows of four mandrels oreight mandrels in all. This is, of course, semidiagrammatic and notintended to be limiting.

Four posts 31S depend from the depressed central section 76 oftransverse frame member 46 adjacent the corners of the molding head '82,but spaced outwardly therefrom, in support of xed clamping plate 9d.This plate is provided with a plurality of apertures 92 respectivelyaligned with the mandrels Sd and through which the mandrels extend in amolding operation, as hereinafter will be set forth. The plate furthercooperates with portions of the mold 7i? to secure a plastic sheet formolding, as will be set forth hereinafter.

A pair of rods 94 is mounted on the cross head 50 relatively adjacentthe opposite ends thereof. The rods Cil extend through suitable holes inthe transverse frame member 46, and are provided at their lower endswith adjustable stops or spring anchors 96 conveniently comprising nutsand washers. A helical spring 98 encircles each rod and is compressedbetween the transverse frame member de and the corresponding stop orspring anchor or seat 96. Accordingly the cross head Sti and the pushrods ifi are urged resiliently down, Iwhereby to hol-d the followers l2resiliently against cam 49. The transverse frame member lo also isprovided with adjustably fixed stops le@ adjacent its opposite ends andengageable with the cross head Stir to limit downward movement thereof.

The hed frame parts supporting the fixed plate 69 and mold guide 74,such frame part hereinafter being identified by the numeral 162, areprovided at their upper edges with upstanding supports ille whichsupport upper belt guides litio and lower belt guides '108. The guideslite and idd are spaced apart only a short distance, and are providedwith pairs of confronting grooves il@ and M2 respectively.

The guides idd and ltll further are supported at their ends by supportsiid (see FlG. l) upstanding from the frame. The ends of the guides areprovided with oppositely extending and diverging supports comprisingupper supports lie and lower supports M8 and are provided with journalsrotatably mounting a pair of spaced upper rollers l2@ and acorresponding pair of spaced lower rollers E22. Each roller is providedVwith four Vagrooves, one pair near each end, receiving two pairs ofupper tl-belts @24 and two pairs of lower V-belts 126.

The lower roller 122 at the entering end of the machine (the right endas viewed in FIGS. l and 3i) is provided with a sprocket i255 driven bychain i3@ from a sprocket 132, the latter being intermittently driven bysuitable mechanism incorporated in the speed reducer 36. Intermittentmotion mechanisms `are well known in the art, and any suitable type maybe used. Further, the entering end rollers 12d and i2?. are gearedtogether by suitable meshing gears 134iand i3d, whereby the belts 124and i216 are driven intermittently and in synchronism. A web or nlm 13Sof plastic sheet material stock is fed into the machine through therollers mit and li322", at the entering end of the machine, is carriedby the belts 124 and 126 past the molding head 82 and mold 7b andemerges from the machine through the discharge rollers 12d and iZZ asscrap idd. lElastic sheet material preferably is of the thermoplasticvariety, and polystyrene, for example, has been used with success. Thesheet material may be fed from a suitable storage roll or directly froman extruder which makes such forms of sheet material.

In order to insure proper plasticity of the sheet stock, there may beprovided an electric resistance heater 142 (or other suitable type suchas infra-red heaters) suitably supported above the web 13S between theentering end of the machine and the mold and molding head. This heaterconveniently may be supported from a fixed portion of the machine suchas the belt guide 1h55.

In addition to the foregoing, there is provided immediately adjacent theentering end of the mold and molding head, an air pipe Ml connected to asuitable source (not shown) and having jets in the side thereof at 146directing air under pressure to blow finished containers away from themold and onto a conveyor or other suitable means to carry the productsaway.

lt has been found that the containers produced by the above machines arestronger if the plastic sheet material from which they are made isinitially stretched biaxially. Therefore, modification of the machine toaccomplish this is shown in FlG. 4. The plastic sheet material isgripped along its opposite edges by diverging pairs of belts (whichaccomplish the desired transverse stretching) M7 in FlG. 4.

it will be understood that there are a pair of belts above the plasticsheet material along each edge and also a pair of belts below theplastic sheet material along each edge,

F7 J and aligned ywith the upper belts. The belts are preferably backedup by suitable rollers or guide means to maintain sufcient clampingpressure on the edges of the material.

Means is provided for restraining or holding back the sheet material,and it is illustrated as being a roller The surface speed of the rolleris less than the speed of the belts 147, and hence the belts cause thematerial to be stretched longitudinally as indicated by the arrowsAccording to one form of the invention, the plastic Inaterial is feddirectly from the extruder and hence is still warm and pliable. However,in some instances, whether from an extruder or from a storage roll, theplastic may have to be heated to a certain extent, and heating meanssuch as electric heaters or infra-red heaters are provided as necessary.One such heater is indicated at 152.

Subsequent treatment of the plastic sheet material, as to the molding ofthe articles is similar to that previously alluded to, and hereinafterdescribed in greater detail. Further reference to this point is believedunecessary, in View of the use of similar reference numerals to thosepreviously used with the addition of the sufiix (a). As will be notedadjacent the left-hand portion of FIG. 4, the material has beenstretched biaxially as indicated by the horizontal number of arrows.

Referring now to FIG. 5, the molding head 82 may be designated as acombination clamping, cut-olf and mandrel means, and comprises amounting plate 156 having an annular ring recess 158 in the vicinity ofthe mandrel 34 illustrated. In recess 153 is a central depending bossle@ which supports the mandrel 54 and is provided with a plurality ofapertures 161 which are connected to an air inlet pipe 163.

lt will be appreciated, that a manifold or the like is provided toprovide air under pressure concurrently to all cf the inlet pipes 163,there being one such inlet for each mandrel 84. Air is supplied from anysuitable compressor or the like 165 (shown schematically in FIG. 14) toilexible hoses 164 (see FIGS. 2 and 14) through the use of a suitablevalving means 165 or any other comnierically known satisfactoryexpedients. The valve means 165 may be actuated by cam 157 mounted onshaft 33. (lt will be appreciated that the disposition of cam 167 andvalve 165, as shown in FIG. 14, is to be considered semidiagrammatic).

The mandrels 84 as shown are substantially in the shape of the frustrumof a cone and are provided `with substantially ilat bottom surfaces 163.rfhe mandrels 84 are preferably heated by suitable means (not shown) forthe reasons hereinafter set forth. As set forth in my aforementionedapplication, the outlets 161 may be in the mandrel 84 per se if desired.

It has been found that one essential feature of a mandrel 84 is that itdoes not extract any substantial amount of heat from the material beingmolded. lt will be appie ciated that if heat is extracted from thepreviously heated plastic sheet material during the molding operation,the sheet loses its elasticity and resists further forming ordeformation. A predetermined degree of cooling of the material uponcontact with the mandrel is desirable to prevent unwanted sliding of thematerial over the entering end of the mandrel; it is imperative that thesheet is not substantially chilled by the mandrel. Another essential isthat the sheet material must not slide in an uncontrolled manner overthe bottom end of the mandrel. Such sliding results in thinning of thesheet material in the vicinity of the bottom of the mandrel, with aresulting thin bottom for the cup or other container.

The mandrels 34 may be made of wood, plastic or metal. In order to avoidextraction of heat from the sheet plastic material by the mandrel, theremay be pro vided a heater within the mandrel which may be an electricheater having lead wires of suitable types. lt should be emphasized thatthe mandrel does not heat the sheet material which in the case ofpolystyrene has been found U to mold satisfactorily at a temperature of24U-260 F. Metal mandrels, such as aluminum or steel, have been found tooperate substantially satisfactorily if operated at a temperature of F.or 250 F. There is no known explanation at the present time as to whytwo such widely separated temperatures operate satisfactorily, however,actual tests show that this is a fact. Structure or means by whichanti-sliid or anti-slipping qualities are imparted to the entering endof the mandrel will not be discussed as they are set forth in moredetail in my copending Unit-cd States application, erial No. 763,668.

Cavit S5 of the die or mold means 7G is aligned with a correspondingmandrel 84. The upper portion of the cavity is provided with a generallyfrusto-conical shape generally complementary to the mandrel. Adjacentthe bottom of the cavity S6 and complementary to the extended positionof the mandrel 84, with a mandrel and cavity 36 in telescoped relation,the side wall of the cavity is formed with an inwardly directed shouldermeans 17) (best shown in FlGS. l1-l2) to provide a shelf for reasonsthat are deemed important and will become apparent.

The shoulder means 17% (best shown in FIGS. ll and l2) is positioned onthe side walls of the cavity 86 in a manner to denne a relatively largeupper portion 171 which has tapering side walls and a relativelystraight or vertical short second side wall portion 173. The upperextremity of the side walls 171 is defined by the lip or shoulderportion 17e and the shoulder means 170 andthe second or lower portion173 is dened by the inwardly curved bottom end portion 172 and theshoulder means 173. More specifically, the shoulder means 17) per seincludes a first horizontal portion 176, a relatively short verticalportion 1725 and a reversed beveled portion 153. (While theseenlargements as shown are considerably greater than actual size, theyare fairly accurate in terms of proportion.)

As best shown in FIG. 7 of the drawings, the side wall of portion 173 ispreferably vertical or parallel with the axis of the mold cavity and thediameter of the side wall 173 preferably is slightly greater than thediameter of vertical portion 178 of the shoulder means 170. Further, thesecond portion 173 of the side wall is preferably slightly less indiameter than the diameter of the side wall of he first portion 171 atthe smallest point, i.e. immediately adjacent the shoulder 170.

A relatively movable mold element 182 (FIGS. 5-7) located in the base ofthe mold cavity performs a triple function in the manufacturing process.First it serves as the bottom wall of the mold 86. Further, itmechanically moves the bottom portion of a preformed container to itsspaced iinal position. Lastly, it serves as a knock-out plug to removethe completely formed container from the mold cavity as will behereinafter explained. As shown, the knock-out plug or mold element 182is cylindrical in shape and is normally positioned in a bore 183 of themold cavity S6 so that top surface 185' is flush with end surface 172 ofthe cavity. The plug 132 is mounted for relative movement relative tothe mold cavity 315 in two distinct ways. First it is mounted on asuitable stem 134 for movement therewith. A lost motion spring 186 maybe placed adjacent the lower end of the stem 14 to cooperate with abushing (not shown) constantly to bias the stem 184 in a downwardposition as indicated in schematic FIG. 14. The stem 184 and knoclooutand forming plug 182 are mounted for relative movement to the fixedportion of he frame 69 by means of a movable plate which is shown mostclearly in schematic diagram FG. 14. The plate 18S bottoms on fixedframe portion 69 and is movable upwardly therefrom by an actuating post12T-Z which is mounted in a suitable bushing (shown in FIG. 20). Theactuating post 192 has a cam follower 194 mounted at the bottom endthereof which is engaged by a cam 1% which is mounted on shaft As can beecn quite clearly in FlG. 14, rotation of shaft 33 will cause cam 196 toengage roller 194 9 to in turn lift actuating post 192 to in turn causeupward movement of plate 1% which in turn causes a relative movement ofthe knock-out and forming plug 182 relative to the mold cavity S6, thelatter being mounted on separate cam actuated posts 66.

The second relative movement of the plug 182 to the cavity S6 isobtained when plate 188 is bottomed on frame 69 and the cavity 36 ismoved downwardly to cause ejection of the container as will beexplained. The relative sequence of this operation together with otheroperations of the device will become more apparent during the discussionof the operation of the machine.

The knock-out and forming plug 182 is preferably formed of a poroussintered material 197 which permits equalization of uid pressure on bothsides of the plug ltZ. The same result may, of course, be accomplishedby making the element 132 of solid material but providing it with acentral insert of permeable material, i.e. which affords a passagewayfor equalizing pressure differentials for the purposes as will be laterexplained.

As clearly shown in FIG. 5 the upper portion 174 of the mold S6 isrounded at the top end thereof and on the outside of the entering end isa short shoulder 19S which adjoins a relatively vertical annular surface200. This portion of the mold together with clamping and cutoff edge 292of the recess 158 of the mandrel means 84 serves to clampingly engagethe membrane of plastic material after it has been mechanicallypre-drawn by the mandrel portion S4. (This is in accordance with theteachings of my cru-pending application 763,668 aforementioned.)

To clamp the web of plastic material `168 for the mechanical drawingthereof by the rmatndrel 84, an annular ring-like clamping means ZM.cooperates with clamping plate 99 to engage the -web of material justprior to and during the mechanical drawing operation. The lower clampingmeans 2M cooperates :with clamping plate 90 to engage the web ofmaterial just pinior to and during the mechanical drawing operation. Thelower clamping means .2414 is provided with an annular recess 2% whichreceives a helical spring 206 to resiliently rurge surface Zio of theclamping ring 204 into engagement with the thermoplastic material.

Before discussing the sequential operation of the machine, it willperhaps be helpful to identify certain portions of the container in itspreformed state and in its finished state. Hthe completely formedcontainer will be identified with the reference numeral 212 and thepreformed or intermediate stage container will be identified by thereference numeral 2id as shown most clearly in FlG. 7 of the drawings.The preformed container 214 has an upper portion 215 and a lower sidewall portion 216 which together provide the side walls of the preformedcontainer which is of complementary shape to the mold when the plug 182is in the position shown in FlG. 7 of the drawings. The bottom surfaceof the preformed container 218 is immediately adjacent the top surfaceof the plug ltl.

The finally formed false bottom container 212 is depicted in FlG. i0 asit is being removed from the mold and has a double thickness skirtportion 220 and a spaced bottom surface 221 which is spaced from theedge 219 of the skirt or depending portion 226.

Operation The motor 342 is energized causing movement of thethermoplastic web 133 into the machine. Shaft 33 is rotated to causecams 40, 62, 196 and 167 to rotate therewith to cause actuation of theparts in a sequential operation as shall now be described. (For purposesof ease of understanding, the semidiagrammatic view of FIG. 14 will beused in this discussion.) The cams 4t) cause posts tl to move the uppermandrel S4 in a downwardly direction and the cams 62 cause plate 72 tomove upwardly which in turn causes the mold cavity d6 and plug it?. tomove upwardly.

CJI

As the shaft 3d rotates, the mandrel means 84 and the mold cavity do arebrought towards each other in a mauner to first cause the under clampingmeans 2M to engage the material 133 to clamp it relative to clampingplate to form an intermediate clamping arrangement. Thereafter themandrel Slt engages the material 13 until the mechanical draw iscompleted and the ring 158 of the mandrel means and edge Z612 thereonengage and lampingly hold the material 13h against portions 174 and 19?as shown in FIG. 6.

At this time cam 167 has rotated into engagement with valve to openpassageway led to the air pressure supply means 165 to afrord a pressuredifferential to the membrane 138 through inlet 163 and outlets 161 ofportion 164) of the mandrel. As shown in FlG. 7, a positive pressureshown by the directional arrows, causes separan tion of the heatedthermoplastic material from the mandrel S4, and engagement of thematerial 13d with the side walls of the mold cavity to take acomplementary configuration thereto. Immediately after the material 138assumes the position shown in PEG. 7 and while the pressure diiferentialstill is in existence, cam member 1% actuates movable plate ltl causingplug 132 to move relative to cavity 86 from its position shown in FIG. 7to the position shown in FlG. 8. lt is to be emphasized that the timingof this movement of the plug lit?. must occur very shortly after theoperation shown in FIG. 7 and preferably is less than a tenth of asecond thereafter. The relative diameter of 'the plug 182 and the secondpor tion 173 of the side walls is such that it causes the material onthe bottom half of the side wall second portion '73 to fold back andadhere to itself. As the plug 182 moves relative to the portion 173 ofthe mold, the preformed container walls 216 peel oil the side wallsrather than losing their identity such as would occur in a pressure orinjection molding type of action` It is thought that this occurs becausethe side walls 173 are relatively cool which causes an almostinstantaneous partial setting of the preformed container wall portion216, so as to allow the walls to retain an identity until they are inthe position shown in FG. 8 whereupon the inner surfaces more or lessiiow together.

The top surface of the combination knock-out plug and forming member`182 is brought into substantial alignment with the reversed taperportion of the shoulder means 17@ to cause the marginal edges of thematerial forming the preformed container portion 213 to adhere to theside walls adjacent the tapered portion 181i. Thus the bottom portion ofWalls 216 and bottom portion Z13 of the preformed container 214 aremoved to their final position and held there by the adherence to theside walls in a position adjacent the shoulder means 17d, there being atight seal completely around the margin of the bottom portion 2118 inits iinal form.

To allow quick retraction of the combination lknockout plug and formingmember 132 to its original position at the bottom of the mold 126 whileallowing the bottom portieri of the container and the double thicknessof the side wall skirt portion to remain in a position shown in FIG. 8,the knockout plug is permeable so that it may be retracted withoutcreating a vacuum immediately adjacent the bottom wall 21S of the formedcontainer. As mentioned earlier in the specification, a small insert ofa permeable character in the plug 132 is suicient to prevent a vacuumfrom forming adjacent the material and the plug when removing same, andit is not necessary to cause a positive pressure in this area toeflicaeiously move the knocked-out plug 1%2 back to its spaced relationor position at the bottom of the mold. As aforementioned, at the sametime that the plug 1&2. is being raised to its second position adjacentthe shoulder 179, the air pressure differential create by the cam 167remains in effect. The air pressure does two things, namely, provides aresilient bias so as to cause the bottom portion Z13 of the container tobe formed in a straight manner and 'll secondly helps to chill the warmthermoplastic material so it will retain its formed state.

While the l'nocl:-out and forming plug 182. is being retracted, the airpressure is released and the combination cut off, clampinc and mandremember is moved downwardly to its third position to shear e formedcontainer from "l` ren 'ng scrap material Mtl as shown in FlG. and thechilling tu@ n. action of the mold cavity on the thermoplastic materialcauses the container 212 to shrink rather uniformly throughout itsextent (except where held at the top of the cavity) so as to move theside walls of the skirt portion 22.9 inwardly a predetermined dimensionand sumciently to be clear of the shoulder means 17@ (as shown in FIG.9). Thus, after a short time delay, and after the mandrel is moved up toits original position by cams 40, when cams d? move the plate 72. andcavity S6 downwardly relati e to the plug 182 (which bottoms on plateand fixed frame 65), the top surface lul of the plug .1.32. engages thedouble thickness slrirt portion to eject the formed container from themold, whereupon the formed contai er 212 is moved for packaging by theair jets .lo as n* oned hereinbefore. While the formed container Zr is bejected from the cavity S5 and blown away by the Jiets 11rd, thematerial 13E is simultaneously moved into position for the new cycle tobegin.

The time cycle of the operation above described when applied to cups isapproximately two seconds, broken down as follows:

(lt should be noted that this is an example only, as the cycle will bevaried depending on the coniiguration and size of the container, thispar icular cycle pertains to thin wall containers such as seven ouncecups having a final wall thickness of live to tcn thousandths of aninch.)

Approximately one third of the cycle time (two-thirds of a second) isrequired for the simultaneous happening of the movement of the fresh webstock 33 into position for engagement with the underside of the clampingmeans 9d au l the ejection of the formed container 212 from the moldcavity S6 by the plug 1552 when the cavity S6 is moved downwardlyrelative to the plug. Approximately one third of the time (twothirds ofa second) is required for the simultaneous movement of the cavity doupward and the mandrel means S4 downward to clamp the materia] 133 andmechanically draw same to the position shown in FIG. 6. The other orremaining one third of the time cycle accomplishes the three stagesshown in FIGS. 7, 8 and 9. However, of this last one third of the cycle(tv/@thirds of a second), by far the greatest portion of the time isutilized in the cutol of the rim of the vtormed container and theretraction o the mandrel toward its starting position to affordclearance for the ejection of the formed container 212. Stated anotherway, only a very small fraction of this two-thirds of a second isrequired to preform the container 2li? by the opening of valve lofi, andthe movement of the plug 1.52 from the bottom of the cavity to itsposition adjacent the shoulder means 178- and its return to the bottomof the cavity Se and the release of the valve 1.55 to release thepressure diilerential.

An alternate method of actuating the combination knock-out and formingplug l?. relative to the mold cavity 35 for moving the container bottomportions in the inal forming stage, is shown in FlG. 14a where in likearts have been denon* "ed lith primed numerals. Only tie operation ofthe plug 132 has been schematically presented, it being und ood that theother operations are accomplished substanr lly as shown in FIG. 14- andFIGS. 1 thru of the drawings aforementioned. As shown in FG. 14a the airsunoly has a sii 'lar valve means s55 which allows mandrel S4 throt Onthe downstream sid of outlet 163 is suitau assagcway means incl ,ifflexible tubing 22T: which is attached to an outlet 22.3 for actuatingan air cylinder 221. No timing device is needed to cause the aircylinder 224 to actuate subsequent to the movement of the air pressurearound mandrel Sii to form the material as shown in FIG. 7 since thetime differential imposed by the time it takes for the pressure front.to reach the second outlet downstream from the first outlet 163 makescertain that the combination knockout and forming plug 182 moves up toform the bottom portion of the false bottom container subsequent toengagement of the thermoplastic material to the confines of the mold 35.lt will also be apparent that the time differential is very short.Another way (not shown) to accomplish the same result is to have two airlines at a f-connection downstream of the valve means 165, one linegoing to the outlet 163' and the second line going to the actuator 224.The second line should be slightly longer than the iirst air line and inactual test it has been found that a dilerential in length of only twoinches gives the desired short interval between the wo operations.

Another alternate embodiment of the invention as shown in FGS. l5 thru17 is portrayed will similar parts identified by the same referencenumbers double primed. In this latter embodiment, the knock-out plug 132does not physically move the material in the forming operation asheretofore in the other embodiments. Rather, plug 13j. has an insert 197of sintered metal which serves as an outlet for a second source of fluidpressure attached to source 166 which is communicated through a supplypipe 226 which is formed in plug 152". Thus the lluid pressure causesthe movement of he bottom 21.25

of the preformed container while plug 182 remains stationary. A heater2.23 is preferably formed directly into the knock-out plug 182" (asdiscussed with the earlier embodiments but not hewn), having suitableleads and 232 extending therefrom. The plug 132 is preterably sealedrelative to the mold portion "5"" by suit- 0J able means 2.34. Alsoventing means 236 is provided for egress of trapped air during thepreforminr1 stage.

ln this embodiment separate valving must be used for pipe 226 since theair pressure utilized in preforming the container through outlets 161"associated with mandrel 84 as shown in HG. 15 must be released prior toiorming a positive pressure through supply pipe 226 in the plug 1.32".As shown, the supply pipe may help create the pressure differential usedin prelorming as shown in FIG. 15 by evacuation, or may be used tocreate the pressure differential alone by creating a vacuum on theunderside of the mechanically drawn container, thereby drawing thematerial into the position shown in EG. 15. In this latter event theoutlets 161" and supply pipe m3 may be eliminated.

As shown in FG. 16, the bottom 1.68" of the mandrel 34" also serves thefunction of providing abutment means or stop upon which the bottomportion 213 of the preformed container 211i impinges when a positivepressure is introduced through supply pipe 226 to thus allow the bottom221 of the linally formed container 2&2 to obtain a regular Hat surface.lt is necessary in this embodiment to vary the sequential operation bycausing the cutoir` step to be prior to the movement of the preformedcontainer bottom portions 21S, the remainder of the container being heldin engagement in tilted position around the periphery at the lip of thecontainer by the combination cutoff and clamping means. Thus, in thisembodiment, the mandrel 34 first mechanically draws the material, thenit is molded to the preformed state by the air pressure differentialcreated either by outlets 26, or 161 or both, then the mandrel 84 ismoved downwardly just adjacent the shoulder means 17d" in the moldcavity the bottom surface 16S thereof to serve as a mold member when areversed pressure differential is placed on the material as shown inPEG. 17. T1 e shoulder means l'li in the mold cavity prevents thematerial from owiug up the sides intermediate the mandrel 34 and themold cavity and thus a false bottomcontainer 2512. is formed having thecharacteristics aforementione Then, as before, the mandrel 34 is removedupwardly and the container 212 is allowed to shrink sutliciently so thatwhen the mold is moved downwardly relative to the plug IlSE thecontainer is ejected as before.

From the foregoing description it will be apparent that the machine iswell adapted to mass manufacturing techniques, and that by the methodsemployed, a `container of superior characteristics with a false orcon-caved bottom characteristic is produced.

Although specific embod-iments have been shown and described, it is withfull awareness that many modiiications thereof are possible. Theinvention, is not to be restricted except insofar as is necessitated bythe prior art and by the spirit of the appended claims.

This application is a division of my prior application 840,604 tiledSeptember 17, 1959, and now Patent 3,059,-

l() granted October Z3, 1962.

l claim:

1. Apparatus for forming a thin wall false bottom container from thinheated thermoplastic material, comprising, mandrel means formechanically drawing tie thermoplastic material, mold means cooperablewith said mandrel means and said thermoplastic material, means forintroducing fluid pressure to one side of the thermoplastic material tocause separation from the mandrel means and engagement with mold meansto preform a container having side walls, a bottom portion, and an openend portion, and means associated with said mold means for quicklymoving the bottom portion of the preformed container toward the open endthereof so that a portion of the side walls fold 4back upon and adhereto themselves to thereby form a thin wall false bottom container.

2. Apparatus for forming a thin wall false bottom container from thinheated thermoplastic material, comprising, mandrel means formechanically drawing the thermoplastic material, mold means having alongitudinally recessed first portion and a relatively movable endportion cooperable with said mandrel means and said thermoplasticmaterial, means for introducing -i'luid pressure to one sid-e of thethermoplastic material to cause separation from the mandrel means andengagement with said first and end portions of said mold means topreform a container having side walls, a bottom portion, and an open endportion, and means associated With said end portion of said mold meansfor quickly moving the bottom portion of the pre-formed container towardthe open end thereof so that a portion of the side walls fold back uponand adhere to themselves to thereby form a thin Wall false bottomcontainer.

3. Apparatus for forming a thin wall false bottom container from thinheated thermoplastic material, comprising, heated mandrel means formechanically drawing the thermoplastic material, mold means having arelatively cool side wall portion defining a cavity and a relative-lyheated end portion cooperable with said mandrel means and saidthermoplastic material, means for introducing fluid pressure to one sideof the thermoplastic material to cause separation from the mandrel meansand engagement with side wall and end Wall portions of the mold means topreform a container having side Walls, a bottom portion, and an open endportion, and means tor quickly moving the bottom portion of thepreformed container in engagement with the heated end portion of themold means and a portion of the side walls adjacent thereto toward theopen end thereof so that said portion of the side walls fold back uponand adhere to themselves to thereby form a thin wall false bottomcontainer.

4. Apparatus for forming an integral thin wall false bottom containerfrom thin heated thermoplastic material, comprising mandrel means formechanically drawing the llithermoplastic material, mold means having aside wall portion and a relatively movable end portion having first andsecond positions relative to said side wall portion, said side wallportion being characterized by shoulder means positioned thereon in amanner to be adjacent said end portion when the latter is in its secondposition and to be spaced therefrom when said end portion is in its rstposition, said mold means being cooperable with said mandrel means andsaid thermoplastic material, means for introducing fluid pressure to oneside of the thermoplastic material to cause separation from the mandrelmeans and engagement with the side wall and end portion of the moldmeans to preform a container having side walls, a bottom portion, and anopen end portion, and means associated with said end portion of the moldmeans for quicldy moving the bottom portion of the preformed containertoward the open end thereof and into alignment with said shoulder meansso that a portion of the side Walls `fold back upon and adhere tothemselves to thereby xediy position said bottom portion of thecontainer adjacent said shoulder means to form a thin wall false bottomcontainer.

5. Apparatus for forming a thin wall false bottom container from thinheated thermoplastic material, comprising mold means cooperable withsaid thermoplastic material, means for introducing fluid pressure to oneside of the thermoplastic material to cause engagement with said moldmeans to preform a container having side walls, a bottom portion, and anopen end portion, and means for quickly moving the bottom portion of thepreformed container and a small portion of the side walls toward theopen end thereof so that said small portion of the side walls fold backupon and adhere to themselves to thereby form a thin wall false bottomcontainer.

6. Apparatus for forming a thin wall false bottom container from thinheated thermoplastic material, comprising, mandrel means formechanically drawing the thermoplastic material, mold means cooperablewith said mandrel means and said thermoplastic material and having firstand second relatively movable portions, means for introducing fluidpressure to one side ofthe thermoplastic material to cause separationfrom the mandrel means and engagement with the rst and second portionsof the mold means to preform a container having side walls, a bottomportion, and an open end portion, and means associated with said moldmeans for quickly moving the second portion of the mold means relativeto the first portion to engage the bottom portion of the preformedcontainer and move the bottom portion toward the open end thereof and toa predetermined position so that a portion of the side Walls fold backupon and adhere to themselves to thereby form a thin wall false bottomcontainer.

7. Apparatus for forming a thin wall false bottom container from thinheated thermoplastic material, comprising mandrel means for mechanicallydrawing the thermoplastic material, mold means cooperable with saidmandrel means and said thermoplastic material and having first andsecond relatively movable portions, fluid pressure means includingsupply means, passageway means, first outlet means to said passagewaymeans and second outlet means in said passageway means spaced from anddownstream of said tirst outlet means, said irst outlet means beingassociated with said mandrel means for introducing fluid pressure to oneside of the thermoplastic material to cause separation thereof from themandrel means and engagement with the first and -second portions of themold means to preform a container having side walls, a bottom portion,and an open end portion, and said second outlet means being associatedwith said mold means for actuating the moving of the second portion ofthe mold means relative to the first portion to in t-urn engage thebottom portion of the preformed container and move the lbottom portiontoward the open end thereof and to a predetermined position so that aportion of the side walls fold back upon and adhere to themselves, thetime differential of separation of the thermoplastic material from themandrel means for engagement with the mold means and actuation of thesecond portion of the mold means being a function of the time requiredfor the pressure of the supply means to be received at the second outletmeans less the time it is received at the iirst outlet means upstreamthereof.

S. Apparatus for forming a thin wall false bottom container from thinheated thermoplastic material, comprising, heated mandrel means formechanically drawing the thermoplastic material, mold means having arelatively cool side Wall portion dening cavity and relatively heatedend portion cooperable with said mandrel means and said thermoplasticmaterial, means for introducing a first fluid pressure differential tothe thermoplastic material to cause separation from the mandrel meansand engagement with side wall and end wall por ions of mold means topreform a container having side walls, a bottom portion, and an open endportion, and means associated with said end portion for introducing asecond fluid differential for quickly moving the bottom portion of thepreformed container positioned in engagement `with the heated endportion of the mold means and a portion of the side walls adjacentthereto toward the open end thereof and to a second position so thatsaid portion of the side walls fold baci; upon and adhere to themselvesto thereby form a thin wall false bottom container.

9. Apparatus `for forming an integral thin wall false bottom containerfrom thin heated thermoplastic material, comprising heated mandrel meansfor mechanically drawing the thermoplastic material, mold means having aside wall portion containing cooling means and a relatively movable endportion having first and second positions relative to said side wallportion, said end portion being characterized by having heating meanstherewithin and fluid pressure outlet means associated therewith, saidside wall portion being characterized by shoulder means positionedthereon in a manner to be adjacent said end portion when the latter isin its second position and to be spaced therefrom when said end portionis in its first position, said mold means being cooperable with saidmandrel means and said thermoplastic material, means associated withsaid mandrel means for introducing fluid pressure to one side of thethermoplastic material to cause separation from the mandrel means andengagement with the side wall and end portions of the mold means topreform a container having side walls, a bottom portion, and an open endportion, and means for supplying fluid pressure to said outlet meansassociated with said end portion of the mold means when said end portionis in its tirst position to quickly move the bottom portion of thepreformed container toward the open end thereof and into alignment withsaid shoulder means so that a portion of the side walls fold back `uponand adhere to themselves to thereby tixedly position said bottom portionof the container adjacent said shoulder means to form a thin wall falsebottom container, and means causing relative movement of said side walland end portions to position said end portion in its second position toafford ejection of the false bottom container from the mold means.

it). Apparatus for forming a thin Wall false bottom container from thinheated t`.ermoplastic material, comprising mandrel means formechanically drawing the thermoplastic material, said mandrel meansbeing characterized by side walls of generally truste-conical shape,mold means cooperable with said mandrel means and said thermoplasticmaterial and being characterized by side walls delining a cavity ofgenerally truste-conical shape and a relatively movable end portion,said side walls being characterized by a iirst portion, a second portionand a shoulder portion joining said first and second portions, said endportion of the mold means having a diameter less than the diameter ofsaid second portion of the side walls and telescopingly relativelymovable therewithin,

1 ,f r. '0 said shoulder portion having a diameter greater than said endportion "nd less than said iirst and second portions of the side Wallisof mold means, said second portion of the side walls aving a diameterless than said first portion of the side walls, for introducing fluidpressure diflerential to the thermoplastic material to cause engagementof the material with the side walls and end portion of the mold means toperform a complementary shaped container having side walls, a bottomportion, and an open end portion, and means associated with said endportion of the mold means for quickly moving the bottom portion of thepreformed container in contact with the end portion of the mold meansand a portion of the side walls of the container in contact with aportion of the second portion of the side walls toward the open end ofthe container so that a portion of the side walls fold back upon andadhere to themselves and the bottom portion of the cor-.ainer is alignedwith and marginally adheres to the side walls of the container adjacentthe shoulder in the side wells o-f the mold means to thereby form a thinwail bottom container.

ll. Apparatus for forming a double thickness container portion on asheet formed plastic container comprisinf:

(n) container mold means having a folding means portion operable to foldsheet plastic material without substantial stretching thereof and afixed portion,

(b) means for disposing heated thin sheet plastic material in proximityto said folding means portion and lined portion of said mold means,

(c) means chilling said mold means to a temperature substantially belowthe temperature of said heated material,

(d) means stretching said plastic material and causing same to engagesaid chilled mold means including said folding means portion in apreform shape of predetermined thickness, and

(e) means actuating said folding means portion of said mold leansimmediately subsequential to the engagement of the plastic material withsaid chilled mold means and prior to removal of a substantial portion ofthe heat from the preformed container, to cause portions of thepreformed container to fold in a manner substantially without furtherstretching thereof and provide a double thickness container portion on asheet formed container,

12. The apparatus set forth in claim ll wherein the means stretching thematerial set forth in (d) and the means actuating the folding meansportion of the container mold means set forth in (e) are fluid pressuremeans connected to a common source of supply, the outlet to the meansset forth in (e) relative to the outlet for the means set forth in (d)being arranged so that fluid pressure emanating from the common sourceof supply reaches the means (d) just slightly prior to reaching themeans (e).

13. The apparatus set forth in claim 1l wherein the container mold meansfixed portion denes the open mouth portion of a container and thecontainer mold means folding means portion defines the bottom wall ofthe container, the mold cavity outline defined by the fixed portionbeing of larger diameter than that defined by the folding means portion,the folding means portion being movable toward the open mouth portion ofthe container sold means the folding means portion of the mold meansbeing initially disposed a lirst predetermined distance from the openmouth portion of the mold means during the initial stretching of theplastic material causing same to engage the chilled mold means topreform a container of a lirst height, the actuation of the foldingmeans portion of the mold means to move same toward the open mouthportion causing the side walls of the preformed container to fold andreduce the overall height of the finished container as compared to itspreform shape.

i4. Apparatus for forming a thin wall container from thin heatedthermoplastic sheet material comprising prestretch means for stretchinx7the thermoplastic material to a rst preform shape, chilled mold meanshaving a temperature substantially below the temperature of said sheetmaterial cooperable with said prestretch means and said thermoplasticmaterial, said chilled mold means including a movable folding meansportion, said movable folding means portion being operable to move andfold said thermoplastic material substantially without stretchingthereof, pressure differential means for introducing a uid pressuredifferential to said thermoplastic material to cause movement of thematerial from its preform shape 4into engagement with said chilled moldmeans including said folding means portion, and actuation meansassociated with said mold means for quickly moving the movable foldingmeans portion subsequent to engagement of the material with said foldingmeans portion to thereby fold the material without substantialstretching thereof and provide a double thickness portion on said thinwall container.

18 15. The apparatus set forth in claim 14 wherein said folding meansportion of said molding means is further characterized as includingmeans for ejecting said container from said chilled mold meanssubsequential to the formation of the double thickness portion on saidthin wall container.

References Cited in the le of this patent UNITED STATES PATENTS

1. APPARATUS FOR FORMING A THIN WALL FALSE BOTTOM CONTAINER FROM THINHEATED THERMOPLASTIC MATERIAL, COMPRISING, MANDREL MEANS FORMECHANICALLY DRAWING THE THERMOPLASTIC MATERIAL, MOLD MEANS COOPERABLEWITH SAID MANDREL MEANS AND SAID THERMOPLASTIC MATERIAL, MEANS FORINTRODUCING FLUID PRESSURE TO ONE SIDE OF THE THERMOPLASTIC MATERIAL TOCAUSE SEPARATION FROM THE MANDREL MEANS AND ENGAGEMENT WITH MOLD MEANSTO PREFORM A CONTAINER HAVING SIDE WALLS, A BOTTOM PORTION, AND AN OPENEND PORTION, AND MEANS ASSOCIATED WITH SAID MOLD MEANS FOR QUICKLYMOVING THE BOTTOM PORTION OF THE PREFORMED CONTAINER TOWARD THE OPEN ENDTHEREOF SO THAT A PORTION OF THE SIDE WALLS FOLD BACK UPON AND ADHERE TOTHEMSELVES TO THEREBY FORM A THIN WALL FALSE BOTTOM CONTAINER.